I. Field of the Invention
The present invention relates to a transfer boom. More particularly, the present invention relates to a transfer boom adapted for suspension from a reciprocal shuttle carriage.
II. Description of the Prior Art
An example of a transfer boom assembly is disclosed in U.S. Pat. No. 4,650,234 which discloses a transfer boom assembly having an elongated boom arm of circular cross section. A multiple hole pattern is extruded throughout the length of the boom to be used as air passages, thereby eliminating the need for pneumatic hoses.
These boom arms are mounted to the transfer boom assembly by a clamp positioned over and around the boom arm and fixedly attached thereto. The clamp provides sockets within which is mounted spreader bars. Spreader bars extend perpendicular to the boom arm and support Venturi vacuum cup assemblies. The vacuum cups engage and hold a workpiece to enable it to be carried to or removed from a work station. These vacuum cups are activated pneumatically and/or electrically, thereby requiring air or electric current to be fed to the vacuum cups via exposed hoses or electrical wires.
Although this previous transfer boom assembly provides interior air passages and protected passages for wires and hoses, the assembly itself is dense. The heaviness of the boom arm may cause it to sag during operation. The addition of multiple spreader bars extending from the boom arm creates an even heavier assembly and a greater chance of sagging or bending of the boom arm under the weight of the workpiece.
A further disadvantage of these previously known transfer boom assemblies is the clamping assembly used for mounting the spreader bars to the boom arm. These previously known clamping assemblies are bulky and awkward to handle. These clamps are of multiple piece assembly which may require constant readjustment as they are not permanently affixed to the boom arm. The clamp, along with the spreader bars, may rotate about the boom arm under the weight of the workpiece assembly.